Skip to main content

Putting Fly Ash to Use

Fly ash is perhaps the best known type of coal ash. It is a powdery material made up of tiny, separate glass spheres. Chemically, fly ash consists primarily of silicon, aluminum, iron and calcium oxides.

The most common application for AEP fly ash is as partial replacement for cement in concrete, concrete products and grouting applications. By replacing a portion of the cement in a mix with AEP fly ash (usually 15% to 30%), raw material costs are reduced, while the ultimate strength and quality of the concrete are improved.

Advantages of Fly Ash in Concrete

  • Lower cost
  • Improved workability
  • Greater ultimate strength
  • Lower permeability
  • Less thermal cracking
  • Increased sulfate resistance
  • Easier to pump
  • Improved finishing characteristics

Controlled Density Fill

Controlled density fill is a combination of cement, fly ash, sand and water. This controlled-strength fill material requires no compaction, and yet is easy to excavate. This adds up to excellent performance that prevents future subsidence with low replacement costs.

Engineered Structural Fills

AEP fly ash is inexpensive and light-weight. By using fly ash as a fill material, poor load-bearing soils and uneven terrain can be converted into useable land. Large structures have been constructed on fly ash fills.

Soil Amelioration/Reclamation

By mixing basic AEP fly ash with very acidic soils, the pH of the soil can be adjusted to allow vegetation to grow. This technique is especially effective in reclaiming surface-mined areas. Soil improvements can be obtained at a much lower cost than with most other alternatives.

Additional fly ash applications:

  • Paints and coatings
  • Plastics
  • Abandoned-mine subsidence
  • Soil stabilization
  • Lightweight aggregate
  • Sludge fixation and stabilization
  • Adhesives
  • Raw material in manufacturing of cement